This is a prospective, randomized (1:1), double-blind, multi-center, Phase II clinical study to test the safety and efficacy of a recombinant chimeric anti-tissue factor antibody (ALT-836) versus placebo in patients with sepsis and acute lung injury/acute respiratory distress syndrome (ALI/ARDS). This study was divided into two parts and the first part of the study has been completed. In the first part of the study, sixty patients were randomized at a 1:1 ratio to receive one dose of the study drug or placebo. In the second part of the study, ninety patients will be randomized at a 1:1 ratio to receive a multi-dose treatment regimen of single doses every 72 hours up to a maximum of 4 doses of the study drug or placebo, provided there are no safety concerns.